Oven Not Preheating Properly: DIY Troubleshooting Guide

Quick Answer

If your oven is not preheating properly, the most common cause is a weakened gas igniter or a burnt-out electric bake element. Start by checking if the bottom element glows red (electric) or if the igniter glows bright white and lights the gas (gas) within 60 seconds.

Look, when your oven won't preheat, it's almost always a heating component that's given up, not the thermostat everyone assumes it is. I've shown up to hundreds of these calls and nine times out of ten it's a $40 igniter or bake element. Ignore it too long and your control board starts working overtime to compensate, and those boards run $200 to $400 to replace.

GenericOvenSeverity: moderateDifficulty: intermediate92% DIY Success

Time to Fix

30–90 min

Difficulty

intermediate

Parts Cost

$20 – $85

Tools Needed

Phillips #2 screwdriver, 1/4 inch nut driver

Oven Not Preheating Properly: DIY Troubleshooting Guide

OK so preheating problems are usually pretty cheap to fix if you catch them early. I had three oven calls last week and two were bad igniters. Most homeowners spend $30 to $80 in parts and fix it themselves in under an hour. The trick is knowing which part to test first so you don't throw money at the wrong thing.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Weak or failing gas bake igniter40%

Burnt out electric bake element30%

Faulty oven temperature sensor (RTD)15%

Malfunctioning oven control board relay10%

Blown thermal fuse or wiring issues5%

Symptoms You May Notice

It takes 45 minutes or more to preheat to 350°F when it used to do it in 10 or 15.
Cookies burn black on top but the bottoms are raw and underdone, which means the broil element is compensating because the bake element isn't pulling its weight.
Your oven display says preheat is done but you stick an oven thermometer in there and it's reading 180° instead of 350°.
On a gas oven, you smell gas for a few seconds after turning it on but the flame either takes forever to catch or doesn't light at all.
There's a repetitive clicking noise from the back of the oven that just keeps going, which is the igniter trying and failing to spark the gas.

Can you reset a Generic oven to clear the NOT-PREHEATING code?

Honestly, most preheating problems are hardware failures, not software glitches, so there's no magic reset that'll fix a broken element. But try this anyway: flip the oven's breaker off and leave it off for a full 10 minutes, then restore power. Sometimes a stuck relay will reset this way. If the problem comes back on the first use, something physical needs to be replaced.

Tools Required for Diagnosis

Phillips #2 screwdriver1/4 inch nut driver5/16 inch nut driverDigital multimeter with ohms and AC voltage settingsWork glovesFlashlight or headlamp

Service / Diagnostic Mode

On most modern ovens, press and hold the 'Bake' and 'Broil' buttons or 'Cancel' for 5 seconds to enter the error code history mode.

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Did the fix not work?

If the problem comes back after following these steps, a component has permanently failed and needs replacement. Check the specific error code your oven is showing:

NO-HEAT Error →

ComponentComponent Under Test

Expected Range20–1100 ohms

ConditionIf Open (OL) or infinite, replace component.

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Bake Heating ElementWPW10308477 · $35–$85	WPW10308477	$35 – $85
Gas Oven IgniterDG94-00520A · $25–$70	DG94-00520A	$25 – $70
Oven Temperature Sensor316233903 · $20–$50	316233903	$20 – $50

Frequently Asked Questions

Why does my oven take 45 minutes to preheat?

Usually it's because one of the two heating elements quit on you. Modern ovens use both the bake element on the bottom and the broil element on top together during preheat to heat up fast. If the bake element's dead, the oven's trying to heat the whole cavity using only the top broil element, which takes forever and cooks food unevenly, burnt on top and raw underneath. Check that bottom element first, look for cracks or burn spots, and test it with a multimeter for continuity.

My gas oven igniter glows orange but the oven won't heat. Is it broken?

Yeah, almost definitely. Here's the thing about igniters, they don't just work or not work, they fade out slowly over time. An old igniter will still glow but it can't draw enough current to open the gas safety valve. That valve needs a specific current threshold to open, usually around 3.2 to 3.6 amps, and a weak igniter doesn't get there. It needs to glow bright white, almost like it's about to burn out itself. Dull orange means replace it. Igniters run about $30 to $60 and it's honestly one of the easier gas repairs you can do yourself.

Can I still use my oven if it's preheating slowly?

I wouldn't. It's not just about inconvenience. If it's preheating slow because of a failing element or a bad sensor, your food's going to cook wrong with burnt tops and raw middles. The bigger problem is your control board is working extra hard to compensate, cycling the broil element constantly to make up for the dead bake element. That wears out a $200 to $400 board way faster than it should. Fix the cheap part now before it kills the expensive one.

How much does it cost to fix an oven that won't preheat?

DIY runs $30 to $80 for the part, whether that's an igniter, bake element, or temp sensor. A service call is typically $150 to $300 depending on your area and the brand. Control board replacement is where it gets ugly, $200 to $450 in parts alone plus labor. At that point you should seriously think about the oven's age and whether it's worth fixing or just putting that money toward a new one.

How do I know if it's the igniter or the gas valve that's bad?

Honestly, it's almost always the igniter. I've replaced probably 300 igniters in my career and maybe five gas valves total. Gas valves rarely fail, and they're also $80 to $150 compared to $30 for an igniter. So always swap the igniter first. If a brand new igniter glows bright white hot and the gas still won't come on after 60 seconds, then yeah, you've confirmed it's the valve. But don't spend money on a valve until you've ruled out the igniter with a new one.

Related Generic Oven Error Codes

Code: NO-HEATOven Not Heating At All

Same Fix on Other Brands

Ge ovenF10: GE Oven F10 Error: runaway Temperature

Models Known to Experience NOT-PREHEATING Errors

This repair applies to most Generic ovens with this error code. Common model numbers include:

JB645DKWW, WFE515S0ES, FFEF3054TS, MGR6600FB, NX58K7850SS, KFEG500ESS, FGEF3036TF, WEG515S0FS, PGB911SEJSS

Written by

Mike Sullivan

Lead Appliance Repair Technician · 20 years experience

Last verified for technical accuracy on May 20, 2024